A heparin-binding erythroid cell stimulating factor from fetal bovine serum has the N-terminal sequence of insulin-like growth factor II.
An 8 kd heparin-binding peptide which stimulates thymidine incorporation in cultures of fetal calf liver erythroid cells was isolated from fetal bovine serum by affinity chromatography on Heparin-Sepharose, ion exchange chromatography, gel filtration and reversed-phase HPLC. The N-terminal sequence of the isolated peptide was identical to the N-terminal sequence of bovine erythrotropin or insulin-like growth factor II (IGF II). The potential heparin-binding site of IGF II is probably situated in the arginine-rich C-peptide region. The affinities of human recombinant IGF I and II were compared with those of apolipoprotein H (a plasma heparin-binding protein) and bovine insulin in a heparin-affinity column. The retention times were in the order: Apolipoprotein H greater than hrIGF II greater than hrIGF I greater than insulin (no retention). This unusual property of IGF II suggests that it may be captured in the extracellular matrix in a similar way to fibroblast growth factor, interleukin 3 or granulocyte/macrophage colony-stimulating factor.
Li
Q G
QG
Endocrine Laboratory, Royal Victoria Hospital, Montreal, Canada.
Blacher
R
R
Esch
F
F
Congote
L F
LF
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002846:Chromatography, Affinity; D004920:Erythropoiesis; D005109:Extracellular Matrix / Q000502:physiology; D006133:Growth Substances / Q000032:analysis*; D006493:Heparin / Q000032:analysis*; D008969:Molecular Sequence Data
D006133:Growth Substances; D006493:Heparin